+
+-- Check precedence of (arg op) or (op arg) respectively
+-- If arg is itself an operator application, its precedence should
+-- be higher than that of op
+checkSectionPrec left_or_right section op arg
+ = case arg of
+ OpApp _ op fix _ -> go_for_it (ppr_op op) fix
+ NegApp _ _ -> go_for_it pp_prefix_minus negateFixity
+ other -> returnRn ()
+ where
+ HsVar op_name = op
+ go_for_it pp_arg_op arg_fix@(Fixity arg_prec _)
+ = lookupFixityRn op_name `thenRn` \ op_fix@(Fixity op_prec _) ->
+ checkRn (op_prec < arg_prec)
+ (sectionPrecErr (ppr_op op_name, op_fix) (pp_arg_op, arg_fix) section)
+\end{code}
+
+Consider
+\begin{verbatim}
+ a `op1` b `op2` c
+\end{verbatim}
+@(compareFixity op1 op2)@ tells which way to arrange appication, or
+whether there's an error.
+
+\begin{code}
+compareFixity :: Fixity -> Fixity
+ -> (Bool, -- Error please
+ Bool) -- Associate to the right: a op1 (b op2 c)
+compareFixity (Fixity prec1 dir1) (Fixity prec2 dir2)
+ = case prec1 `compare` prec2 of
+ GT -> left
+ LT -> right
+ EQ -> case (dir1, dir2) of
+ (InfixR, InfixR) -> right
+ (InfixL, InfixL) -> left
+ _ -> error_please
+ where
+ right = (False, True)
+ left = (False, False)
+ error_please = (True, False)
+\end{code}
+
+%************************************************************************
+%* *
+\subsubsection{Literals}
+%* *
+%************************************************************************
+
+When literals occur we have to make sure
+that the types and classes they involve
+are made available.
+
+\begin{code}
+litFVs (HsChar c) = returnRn (unitFV charTyCon_name)
+litFVs (HsCharPrim c) = returnRn (unitFV (getName charPrimTyCon))
+litFVs (HsString s) = returnRn (mkFVs [listTyCon_name, charTyCon_name])
+litFVs (HsStringPrim s) = returnRn (unitFV (getName addrPrimTyCon))
+litFVs (HsInt i) = returnRn (unitFV (getName intTyCon))
+litFVs (HsIntPrim i) = returnRn (unitFV (getName intPrimTyCon))
+litFVs (HsFloatPrim f) = returnRn (unitFV (getName floatPrimTyCon))
+litFVs (HsDoublePrim d) = returnRn (unitFV (getName doublePrimTyCon))
+litFVs (HsLitLit l bogus_ty) = lookupOrigName cCallableClass_RDR `thenRn` \ cc ->
+ returnRn (unitFV cc)
+litFVs lit = pprPanic "RnExpr.litFVs" (ppr lit) -- HsInteger and HsRat only appear
+ -- in post-typechecker translations
+
+rnOverLit (HsIntegral i from_integer)
+ = lookupOccRn from_integer `thenRn` \ from_integer' ->
+ (if inIntRange i then
+ returnRn emptyFVs
+ else
+ lookupOrigNames [plusInteger_RDR, timesInteger_RDR]
+ ) `thenRn` \ ns ->
+ returnRn (HsIntegral i from_integer', ns `addOneFV` from_integer')
+
+rnOverLit (HsFractional i n)
+ = lookupOccRn n `thenRn` \ n' ->
+ lookupOrigNames [ratioDataCon_RDR, plusInteger_RDR, timesInteger_RDR] `thenRn` \ ns' ->
+ -- We have to make sure that the Ratio type is imported with
+ -- its constructor, because literals of type Ratio t are
+ -- built with that constructor.
+ -- The Rational type is needed too, but that will come in
+ -- when fractionalClass does.
+ -- The plus/times integer operations may be needed to construct the numerator
+ -- and denominator (see DsUtils.mkIntegerLit)
+ returnRn (HsFractional i n', ns' `addOneFV` n')